BERLIN - Research into the use of algae to capture carbon dioxide from the
air is changing the negative reputation of these organisms, often seen as a
plague associated with agricultural fertiliser run-off.

Until very recently, the proliferation algae was interpreted as an
undesirable consequence of the overuse of agro-chemicals, whose immediate
results included skin irritation in humans and the death of aquatic fauna
from lack of oxygen.

But their potential for absorbing one of the principal greenhouse gases --
which cause global climate change -- could be crucial for avoiding
environmental catastrophes. Like terrestrial plants, the algae consume
carbon during photosynthesis.

"We took algae from the ocean, we put it in plastic containers in
greenhouses, where we fed it with carbon dioxide produced by conventional
electric generators," explained Laurenz Thomsen, a bio-geologist from Jacobs
University in the northern German city of Bremen.

"Exposed to solar light, the algae transform the carbon dioxide into biomass
that can later be used as biodiesel, whose combustion doesn't emit
greenhouse gases," he added.

The Greenhouse Gas Mitigation Project (GGMP)
<http://www.irccm.de/greenhouse/project.html> is coordinated by Thomsen,
with cooperation from the Bremen polytechnic university, the Alfred Wegener
Institute for Marine Research, and several companies, including the European
electricity supplier E.ON.

Thomsen has dubbed the small greenhouse "Algenreactor", set up at Jacobs
University, where the algae transform carbon dioxide into organic fuel. The
project is operating at the experimental phase, producing just a half-litre
of biofuel.

"The diesel that we refine here is absolutely organic. It satisfies the
European standards. I'm confident that we will be able to move on to an
industrial phase in the coming months," he added.

Fritz Henken-Mellier, director of the Farge thermoelectric plant just
outside Bremen, agrees with that prediction. Some of the carbon dioxide
emissions from this coal-fired generator were captured by GGMP.

"Surely we need to build a much bigger greenhouse, covering hundreds of
square metres, so that the capture of carbon dioxide and the production of
biofuel correspond to the scope of a commercial energy plant," he said in an
interview for this report.

Henken-Mellier calculates that "the capture of just 10 percent of the gases
emitted by the Farge plant means a reduction of 600 tonnes daily of carbon
dioxide."

According to Thomsen, the area of a greenhouse capable of absorbing the
carbon dioxide from a 350-megawatt electrical plant and transforming it into
biofuel would have to be 25 square kilometres and would cost some 480
million dollars.

The sum is small compared to the cost of conventional crops to produce
biofuel and reduce toxic gases at a scale similar to that of the
"algae-based reactor." An equivalent planting of rapeseed, for example,
could cost as much as 25 times more.

But Thomsen's project doesn't convince everyone. "Those calculations are
very ingenuous," said Karl-Herrman Steinberg, director of one of Europe's
leading algae producers, located in the northern German city of Kloetze.

"The costs of growing algae, the elimination of the water and distillation
of the combustible oil are very high for this to be profitable on an
industrial scale," said Steinberg.

Thomsen admits that the location of the greenhouses should be decided based
on available sunshine. In northern Germany, with relatively few hours of
sunlight, the model would not work. "The greenhouses would have to be built
in the south and southeast of Europe," he said.

"We are already negotiating with German and foreign firms, from Brazil and
India, which manage large algae crops," he added.

The GGMP is not the only project of its kind. During the first global oil
crisis, in the 1970s, U.S. scientists came up with a similar process for
transforming algae into biofuel. But the attempt was abandoned in 1996, when
low oil prices erased the incentives to study organic fuels.

Now, with the current energy and environmental crisis, the U.S. company
GreenFuel <http://www.greenfuelonline.com/>, in the north-eastern state of
Massachusetts, is planning a greenhouse to cover at least one square
kilometre for 2009.

Isaac Berzin, of GreenFuel, says that to capture the carbon dioxide released
by a 1,000 gigawatt generate would require an algae greenhouse between eight
and 16 square km, which could produce more than 150 million litres of
biodiesel and 190 million litres of ethanol.